Biohydrogen production from purified terephthalic acid (PTA) processing wastewater by anaerobic fermentation using mixed microbial communities

• Published in: International journal of hydrogen energy 2010-08, Vol.35 (15), p.8350-8356
• Main Authors: Zhu, Ge-Fu, Wu, Peng, Wei, Qun-Shan, Lin, Jian-yi, Gao, Yan-Li, Liu, Hai-Ning
• Format: Article
• Language: English
• Subjects: Acetates; Alternative fuels. Production and utilization; Applied sciences; Biohydrogen production; Chemical oxygen demand (COD); Continuous stirred-tank reactor (CSTR); Energy; Ethanol; Ethyl alcohol; Exact sciences and technology; Fermentation; Fuels; Hydrogen; Microorganisms; Purified terephthalic acid (PTA); Reactors; Sludge; Specific hydrogen production rate; Waste water; Wastewater treatment
• ISSN: 0360-3199; 1879-3487
• DOI: 10.1016/j.ijhydene.2009.12.003

Purified terephthalic acid (PTA) processing wastewater was evaluated as a fermentable substrate for hydrogen (H 2) production with simultaneous wastewater treatment by dark-fermentation process in a continuous stirred-tank reactor (CSTR) with selectively enriched acidogenic mixed consortia under continuous flow condition in this paper. The inoculated sludge used in the reactor was excess sludge taken from a second settling tank in a local wastewater treatment plant. Under the conditions of the inoculants not less than 6.3 gVSS/L, the organic loading rate (OLR) of 16 kgCOD/m 3 d, hydraulic retention time (HRT) of 6 h and temperature of (35 ± 1) °C, when the pH value, alkalinity and oxidation–reduction potential (ORP) of the effluent ranged from 4.2 to 4.4, 280 to 350 mg CaCO 3/L, and −220 to −250 mV respectively, soluble metabolites were predominated by acetate and ethanol, with smaller quantities of propionate, butyrate and valerate. Stable ethanol-type fermentation was formed with the sum of ethanol and acetate concentration ratio of 70.31% to the total liquid products after 25 days operation. The H 2 volume content was estimated to be 48–53% of the total biogas and the biogas was free of methane throughout the study. The average biomass concentration was estimated to be 10.82 gVSS/L, which favored H 2 production efficiently. The rate of chemical oxygen demand (COD) removal reached at about 45% and a specific H 2 production rate achieved 0.073 L/gMLVSS d in the study. This CSTR system showed a promising high-efficient bioprocess for H 2 production from high-strength chemical wastewater.